1. Field of the Invention
The present invention relates generally to a method of making an elongated article including an extruded member formed from rubber and a tape member bonded to the extruded member. In particular, the present invention is directed to a method of making an elongated article capable of receiving and securing a portion of a glass member, in which the tape member of the article is constructed and arranged to protect the article against wear encountered by sliding of the glass member across the article.
2. Description of Related Art
A conventional glass runner article for an automobile window is illustrated in FIG. 8. The conventional glass runner article includes an elongated member 40 made of rubber having a bottom portion 41. The article further includes a resin tape 42 formed on the bottom portion 41 of the elongated member 40.
It is known to form the elongated member 40 from EPDM (ethylene-propylene-diene copolymer) rubbers by extrusion molding, and thereafter to bond the resin tape 42 (such as polyethylene tape) to the bottom portion 41 of the member 40. The resin tape 42 serves to improve the slidability and durability of the article by protecting the article from wear due to the sliding of the glass window or windshield thereon.
The bonding of the resin tape 42 to the elongated member 40 is accomplished by the method illustrated in FIG. 7. This method involves forming the elongated member 40 continuously with an extruder 50. Prior to vulcanization of the member 40, a reel 51 continuously supplies the resin tape 42, which is pressed against and attached to the bottom portion 41 of the elongated member 40 (which is not yet vulcanized) by a roller 52. The elongated member 40 is then vulcanized by passing the member 40 through a microwave vulcanizer 53 and an electric heat vulcanizer 54 in sequential manner. While passing through the vulcanizers 53 and 54, the resin tape 42 bonded to the bottom portion 41 of the elongated member 40 is heated and melted, which welds the resin tape 42 to the bottom portion 41.
One disadvantage of the above-discussed conventional method is that the resin tape 42 is heated to a temperature above its melting point by heat in the vulcanizers 53 and 54. Consequently, the resin tape 42 excessively melts, stretches to become wavy, breaks, or peels, leading to low bond strength between the resin tape 42 and the member 40. This problem is not peculiar or limited to glass runners for automobiles; rather, this problem is encountered in the production of a variety of extruded articles comprising rubber materials and resin tapes bonded thereto, such as door opening trim weather strips and inner glass weather strips.
In order to address this problem, the present inventor investigated a method of bonding a resin tape to an extruded member of rubber immediately after vulcanization of the member, rather than during passage through the vulcanizers. This method was found to be unsuccessful, since the extruded member of rubber did not have sufficient heat energy to cause the resin tape to weld by simple pressing.